I actually used CCI 200 std large rifle with my .375 loads which utilized over 80 grs of IMR 4831 powder with no issues. Mag primers can sometimes elevate pressures and I only use them when specifically called for with some of the hard to light powders like some ball powders or really large doses of slow burning powders. While it would seem that my .375 loads would scream for mag primers I never used them.

Went to the range today for some testing and found that my best 3 shot groups came from the CCI BR -2's that I use for my cz 550 in .308! Thirty rounds later,my shoulder is a bit tender but at least I have no more plaque on my teeth..!

..how I love the whisper of a finely tuned 308 and the serenity it bestows upon a troubled mind..